Known as a conventional spectroscopic sensor is one comprising an optical filter unit for selectively transmitting therethrough a predetermined wavelength range of light according to an incident position thereof and a light detection substrate for detecting the light transmitted through the optical filter unit. In spectroscopic sensors disclosed in Patent Literatures 1 and 2, for example, the optical filter unit is provided so as to correspond to a light-receiving surface of the light detection substrate and functions as a whole as a filter region for transmitting therethrough light to be incident on the light-receiving surface of the light detection substrate.